In general, a crane and a winch disposed in a nacelle of a wind turbine generator, which are used for maintenance, are designed so as to be used in periodic inspection and therefore have capacities capable of replacing only lightweight components in the nacelle.
Therefore, when severe trouble occurred in large equipment such as a generator or a transformer, large heavy machinery has been used for replacing such large equipment. The potential risk of severe trouble occurring in the large equipment is not so high, but such severe trouble that occurs in the large equipment has a disadvantage that the cost impact is high due to the use of the large heavy machinery.
In order to avoid the above-mentioned problem, various techniques have been proposed for enabling replacement of large equipment without using large heavy machinery (for example, see Patent Documents 1 and 2).
Patent Document 1: European Patent No. 1101934, Specification
Patent Document 2: European Patent Application, Publication No. 1291521, Specification